The exemplary embodiments relate to an optical device having an optical modulation element to modulate the luminous flux emitted from the light source according to image information and to form an optical image and a cooling device for cooling the optical modulation element, and to a projector having the optical device.
Projectors of the related art are used in the presentations at conferences, academy meetings, exhibitions, etc. or in viewing movies in households, or the like. Such a projector has an optical device having a light source, an optical modulation element to modulate the luminous flux emitted from the light source according to image information and to form an optical image, and a plurality of optical components arranged in the front and rear stages of the optical modulation element and to optically convert the incident luminous flux. The optical image formed by the optical device is projected with magnification.
Due to the recent brightness increase and size reduction in the projector, temperature rise is conspicuous on the optical modulation element and optical components arranged within the projector. Meanwhile, these optical modulation element and optical components are not resistive to heat, to readily cause thermal deteriorations. Where a thermal deterioration occurs in the optical modulation element and optical components, a bad effect upon optical image formation is encountered and may possibly raise trouble in maintaining projector functions. For this reason, in the related art a general practice is to employ a cooling system of an air-cooled type to feed a cooling air by way of a fan or the like. However, the air-cooled type is limited in heat radiation capability. Furthermore, in order to secure air feed amount, there is a need to rotate the fan at a high speed and to use a large-sized fan, thus raising a problem of making it impossible or difficult to cope with noise and size reductions for the projector. Consequently, studies have been made on other cooling systems for efficiently cooling the light modulation element and optical components.
In the related art, there is an electronic device having a cooling structure for circulating a coolant (coolant liquid) through the interior thereof and cooling a heat generating element, as a cooling system for solving such a problem (see JP-A-2003-124670, for example). In such a cooling structure, a water-cooled jacket is attached to the CPU as a heat generating element, to connect the water-cooled jacket, the heat-releasing pipe and the pump together by way of a tube. The CPU is cooled by circulating the coolant filled inside by the pump. In case such a cooling structure is employed in the projector optical device to thereby cool the heat of the light modulation element, the light modulation element can be cooled efficiently because the liquid is greater in specific heat and higher in heat transmission power as compared to air. Because of the absence of fan rotation sound and blade noise, noise reduction for the projector can be realized.